SOW-RD62-FINAL · Virtual first article

RD-62

Rational-Duplex pocket slide rule. 125.00 mm log line, G-10 body, laser-marked acrylic plates.

Registry 0.000 mm · limit ±0.015 mm · cursor 75.257 mm · slide +0.000 mm · hairline locked across both faces

Alignment window on the hairline. Stators stay put; the brass slide band moves. Each row is the scale name, the value under the hairline, and the nearest labeled tick. Tap a row to read it.

Scales under the hairline

Upper stator

Slide

Lower stator

Plate, track, and acceptance

Stack

  • Stators and slide core: matte black G-10 Garolite.
  • Overlays: 2-layer cast acrylic, white cap over a black core, 0.5–1.0 mm.
  • Standard lines etch through to the black core. Red and green are deep channels with wiped acrylic ink.
  • Cursor: 1.5 mm optical polycarbonate, wrap-around frame, stainless tension rollers, 0.05 mm red hairline, 1.5× horizontal lens.

Inks

  • Black — C D K J B DF DF₄ CF₄
  • Red — CI DI BI, inverted
  • Green — Q s P H, quadrance and spread

Gauge marks on C and D

q¼, q½ and q¾ sit on the floating-decimal marks 2.500, 5.000 and 7.500. I₄ is the primary index-shift fold at 4.000, boxed. Spread s ≥ 0.90 is asymptotic and is not on the plate; s₂ ends at 0.9000.

Running fit · slide 12.50 × 4.00 mm

12.50 wide · 4.00 thick · tongue 1.50 · groove 1.60 × 1.56
  • Tongues 1.50 mm proud, 1.50 mm high, 1.25 mm shelf above and below.
  • Stator grooves 1.60 mm deep, slot 1.56 mm, +0.06 mm vertical clearance.
  • Slide must travel the full seam under 1.5 N. This article is frictionless.
  • Scale registry, zero to zero: 0.000 mm over the 125 mm line. Acceptance is ±0.015 mm.